lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep

commit df754e6af2f237a6c020c0daff55a1a609338e31 upstream.

It's unlikely that TAINT_FIRMWARE_WORKAROUND causes false
lockdep messages, so do not disable lockdep in that case.
We still want to keep lockdep disabled in the
TAINT_OOT_MODULE case:

  - bin-only modules can cause various instabilities in
    their and in unrelated kernel code

  - they are impossible to debug for kernel developers

  - they also typically do not have the copyright license
    permission to link to the GPL-ed lockdep code.

Suggested-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-xopopjjens57r0i13qnyh2yo@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
lockdep, bug: Exclude TAINT_OOT_MODULE from disabling lock debugging

commit 9ec84acee1e221d99dc33237bff5e82839d10cc0 upstream.

We do want to allow lock debugging for GPL-compatible modules
that are not (yet) built in-tree.  This was disabled as a
side-effect of commit 2449b8ba0745327c5fa49a8d9acffe03b2eded69
('module,bug: Add TAINT_OOT_MODULE flag for modules not built
in-tree').  Lock debug warnings now include taint flags, so
kernel developers should still be able to deflect warnings
caused by out-of-tree modules.

The TAINT_PROPRIETARY_MODULE flag for non-GPL-compatible modules
will still disable lock debugging.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Nick Bowler <nbowler@elliptictech.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Debian kernel maintainers <debian-kernel@lists.debian.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/1323268258.18450.11.camel@deadeye
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: compaction: check for overlapping nodes during isolation for migration

commit dc9086004b3d5db75997a645b3fe08d9138b7ad0 upstream.

When isolating pages for migration, migration starts at the start of a
zone while the free scanner starts at the end of the zone.  Migration
avoids entering a new zone by never going beyond the free scanned.

Unfortunately, in very rare cases nodes can overlap.  When this happens,
migration isolates pages without the LRU lock held, corrupting lists
which will trigger errors in reclaim or during page free such as in the
following oops

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffff810f795c>] free_pcppages_bulk+0xcc/0x450
  PGD 1dda554067 PUD 1e1cb58067 PMD 0
  Oops: 0000 [#1] SMP
  CPU 37
  Pid: 17088, comm: memcg_process_s Tainted: G            X
  RIP: free_pcppages_bulk+0xcc/0x450
  Process memcg_process_s (pid: 17088, threadinfo ffff881c2926e000, task ffff881c2926c0c0)
  Call Trace:
    free_hot_cold_page+0x17e/0x1f0
    __pagevec_free+0x90/0xb0
    release_pages+0x22a/0x260
    pagevec_lru_move_fn+0xf3/0x110
    putback_lru_page+0x66/0xe0
    unmap_and_move+0x156/0x180
    migrate_pages+0x9e/0x1b0
    compact_zone+0x1f3/0x2f0
    compact_zone_order+0xa2/0xe0
    try_to_compact_pages+0xdf/0x110
    __alloc_pages_direct_compact+0xee/0x1c0
    __alloc_pages_slowpath+0x370/0x830
    __alloc_pages_nodemask+0x1b1/0x1c0
    alloc_pages_vma+0x9b/0x160
    do_huge_pmd_anonymous_page+0x160/0x270
    do_page_fault+0x207/0x4c0
    page_fault+0x25/0x30

The "X" in the taint flag means that external modules were loaded but but
is unrelated to the bug triggering.  The real problem was because the PFN
layout looks like this

  Zone PFN ranges:
    DMA      0x00000010 -> 0x00001000
    DMA32    0x00001000 -> 0x00100000
    Normal   0x00100000 -> 0x01e80000
  Movable zone start PFN for each node
  early_node_map[14] active PFN ranges
      0: 0x00000010 -> 0x0000009b
      0: 0x00000100 -> 0x0007a1ec
      0: 0x0007a354 -> 0x0007a379
      0: 0x0007f7ff -> 0x0007f800
      0: 0x00100000 -> 0x00680000
      1: 0x00680000 -> 0x00e80000
      0: 0x00e80000 -> 0x01080000
      1: 0x01080000 -> 0x01280000
      0: 0x01280000 -> 0x01480000
      1: 0x01480000 -> 0x01680000
      0: 0x01680000 -> 0x01880000
      1: 0x01880000 -> 0x01a80000
      0: 0x01a80000 -> 0x01c80000
      1: 0x01c80000 -> 0x01e80000

The fix is straight-forward.  isolate_migratepages() has to make a
similar check to isolate_freepage to ensure that it never isolates pages
from a zone it does not hold the LRU lock for.

This was discovered in a 3.0-based kernel but it affects 3.1.x, 3.2.x
and current mainline.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: fix UP THP spin_is_locked BUGs

commit b9980cdcf2524c5fe15d8cbae9c97b3ed6385563 upstream.

Fix CONFIG_TRANSPARENT_HUGEPAGE=y CONFIG_SMP=n CONFIG_DEBUG_VM=y
CONFIG_DEBUG_SPINLOCK=n kernel: spin_is_locked() is then always false,
and so triggers some BUGs in Transparent HugePage codepaths.

asm-generic/bug.h mentions this problem, and provides a WARN_ON_SMP(x);
but being too lazy to add VM_BUG_ON_SMP, BUG_ON_SMP, WARN_ON_SMP_ONCE,
VM_WARN_ON_SMP_ONCE, just test NR_CPUS != 1 in the existing VM_BUG_ONs.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "lockdep, bug: Exclude TAINT_OOT_MODULE from disabling lock debugging"

This reverts commit 6492a0fb92a35630103cc62a1902018dfef8b46c.
Revert "lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep"

This reverts commit 1a90d01be282f295186d58b42d8cbac1d5d7edc4.
relay: prevent integer overflow in relay_open()

commit f6302f1bcd75a042df69866d98b8d775a668f8f1 upstream.

"subbuf_size" and "n_subbufs" come from the user and they need to be
capped to prevent an integer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
writeback: fix NULL bdi->dev in trace writeback_single_inode

commit 15eb77a07c714ac80201abd0a9568888bcee6276 upstream.

bdi_prune_sb() resets sb->s_bdi to default_backing_dev_info when the
tearing down the original bdi. Fix trace_writeback_single_inode to
use sb->s_bdi=default_backing_dev_info rather than bdi->dev=NULL for a
teared down bdi.

Reported-by: Rabin Vincent <rabin@rab.in>
Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue

commit 977b7e3a52a7421ad33a393a38ece59f3d41c2fa upstream.

When a SD card is hot removed without umount, del_gendisk() will call
bdi_unregister() without destroying/freeing it. This leaves the bdi in
the bdi->dev = NULL, bdi->wb.task = NULL, bdi->bdi_list removed state.

When sync(2) gets the bdi before bdi_unregister() and calls
bdi_queue_work() after the unregister, trace_writeback_queue will be
dereferencing the NULL bdi->dev. Fix it with a simple test for NULL.

LKML-reference: http://lkml.org/lkml/2012/1/18/346
Reported-by: Rabin Vincent <rabin@rab.in>
Tested-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cifs: request oplock when doing open on lookup

commit 8b0192a5f478da1c1ae906bf3ffff53f26204f56 upstream.

Currently, it's always set to 0 (no oplock requested).

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "cifs: request oplock when doing open on lookup"

This reverts commit eb55843061d52fef25fdb3ec88d4d7d87f023db9.
backing-dev: fix wakeup timer races with bdi_unregister()

commit 2673b4cf5d59c3ee5e0c12f6d734d38770324dc4 upstream.

While 7a401a972df8e18 ("backing-dev: ensure wakeup_timer is deleted")
addressed the problem of the bdi being freed with a queued wakeup
timer, there are other races that could happen if the wakeup timer
expires after/during bdi_unregister(), before bdi_destroy() is called.

wakeup_timer_fn() could attempt to wakeup a task which has already has
been freed, or could access a NULL bdi->dev via the wake_forker_thread
tracepoint.

Cc: Jens Axboe <axboe@kernel.dk>
Reported-by: Chanho Min <chanho.min@lge.com>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vfs: fix d_inode_lookup() dentry ref leak

commit e188dc02d3a9c911be56eca5aa114fe7e9822d53 upstream.

d_inode_lookup() leaks a dentry reference on IS_DEADDIR().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NFSv4: Fix an Oops in the NFSv4 getacl code

commit 331818f1c468a24e581aedcbe52af799366a9dfe upstream.

Commit bf118a342f10dafe44b14451a1392c3254629a1f (NFSv4: include bitmap
in nfsv4 get acl data) introduces the 'acl_scratch' page for the case
where we may need to decode multi-page data. However it fails to take
into account the fact that the variable may be NULL (for the case where
we're not doing multi-page decode), and it also attaches it to the
encoding xdr_stream rather than the decoding one.

The immediate result is an Oops in nfs4_xdr_enc_getacl due to the
call to page_address() with a NULL page pointer.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Andy Adamson <andros@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NFSv4: Ensure we throw out bad delegation stateids on NFS4ERR_BAD_STATEID

commit b9f9a03150969e4bd9967c20bce67c4de769058f upstream.

To ensure that we don't just reuse the bad delegation when we attempt to
recover the nfs4_state that received the bad stateid error.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NFSv4: fix server_scope memory leak

commit abe9a6d57b4544ac208401f9c0a4262814db2be4 upstream.

server_scope would never be freed if nfs4_check_cl_exchange_flags() returned
non-zero

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: memcg: Correct unregistring of events attached to the same eventfd

commit 371528caec553785c37f73fa3926ea0de84f986f upstream.

There is an issue when memcg unregisters events that were attached to
the same eventfd:

- On the first call mem_cgroup_usage_unregister_event() removes all
  events attached to a given eventfd, and if there were no events left,
  thresholds->primary would become NULL;

- Since there were several events registered, cgroups core will call
  mem_cgroup_usage_unregister_event() again, but now kernel will oops,
  as the function doesn't expect that threshold->primary may be NULL.

That's a good question whether mem_cgroup_usage_unregister_event()
should actually remove all events in one go, but nowadays it can't
do any better as cftype->unregister_event callback doesn't pass
any private event-associated cookie. So, let's fix the issue by
simply checking for threshold->primary.

FWIW, w/o the patch the following oops may be observed:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0
 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs
 RIP: 0010:[<ffffffff810be32c>]  [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0
 RSP: 0018:ffff88001d0b9d60  EFLAGS: 00010246
 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0)
 Call Trace:
  [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60
  [<ffffffff8103db94>] process_one_work+0x174/0x450
  [<ffffffff8103e413>] worker_thread+0x123/0x2d0

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cifs: fix dentry refcount leak when opening a FIFO on lookup

commit 5bccda0ebc7c0331b81ac47d39e4b920b198b2cd upstream.

The cifs code will attempt to open files on lookup under certain
circumstances. What happens though if we find that the file we opened
was actually a FIFO or other special file?

Currently, the open filehandle just ends up being leaked leading to
a dentry refcount mismatch and oops on umount. Fix this by having the
code close the filehandle on the server if it turns out not to be a
regular file. While we're at it, change this spaghetti if statement
into a switch too.

Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: thp: fix BUG on mm->nr_ptes

commit 1c641e84719429bbfe62a95ed3545ee7fe24408f upstream.

Dave Jones reports a few Fedora users hitting the BUG_ON(mm->nr_ptes...)
in exit_mmap() recently.

Quoting Hugh's discovery and explanation of the SMP race condition:

  "mm->nr_ptes had unusual locking: down_read mmap_sem plus
   page_table_lock when incrementing, down_write mmap_sem (or mm_users
   0) when decrementing; whereas THP is careful to increment and
   decrement it under page_table_lock.

   Now most of those paths in THP also hold mmap_sem for read or write
   (with appropriate checks on mm_users), but two do not: when
   split_huge_page() is called by hwpoison_user_mappings(), and when
   called by add_to_swap().

   It's conceivable that the latter case is responsible for the
   exit_mmap() BUG_ON mm->nr_ptes that has been reported on Fedora."

The simplest way to fix it without having to alter the locking is to make
split_huge_page() a noop in nr_ptes terms, so by counting the preallocated
pagetables that exists for every mapped hugepage.  It was an arbitrary
choice not to count them and either way is not wrong or right, because
they are not used but they're still allocated.

Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
aio: fix io_setup/io_destroy race

commit 86b62a2cb4fc09037bbce2959d2992962396fd7f upstream.

Have ioctx_alloc() return an extra reference, so that caller would drop it
on success and not bother with re-grabbing it on failure exit.  The current
code is obviously broken - io_destroy() from another thread that managed
to guess the address io_setup() would've returned would free ioctx right
under us; gets especially interesting if aio_context_t * we pass to
io_setup() points to PROT_READ mapping, so put_user() fails and we end
up doing io_destroy() on kioctx another thread has just got freed...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>